This
User’s Guide provides execution guidance for and physical description of the
public version of the community Noah LSM.This version of the Noah LSM is a stand-alone, uncoupled, 1-D column version used to
execute single-site land-surface simulations.In this traditional 1-D uncoupled mode, near-surface atmospheric forcing
data is required as input forcing (see Sec 6.0).This LSM simulates soil moisture (both liquid and frozen), soil
temperature, skin temperature, snowpack depth, snowpack water equivalent (and
hence snowpack density), canopy water content, and the energy flux and water
flux terms of the surface energy balance and surface water balance.See Sec 10 for the lineage of key technical
references.

The
public server directory in which this User’s Guide resides also contains the
complete, self-contained Noah LSM
source code file, input control file, input atmospheric forcing file, and
example execution-time LSM output files for a full one-year 1998
simulation.This simulation is valid at
the Champaign, Illinois surface-flux site (40.01 N, 88.37 W) of NOAA/ARL
investigator Tilden Meyers.See Sec 3
for a “Quick-Start” guide to executing the Noah
LSM code in this directory to duplicate the cited 1998 simulation at this
site.To execute Noah LSM simulations at other sites for other initial times, study
Secs 5 through 8.

(Reminder: See Sec 3 for a “Quick-Start”
guide to executing the Noah LSM.)

2.0 MODEL HERITAGE

Beginning
in 1990, and accelerating after 1993 under sponsorship from the GEWEX/GCIP/GAPP
then GEWEX/GAPP Program Office of NOAA/OGP via collaboration with numerous
GCIP/GAPP/GAPP Principal Investigators (PIs), the Environmental Modeling
Center(EMC) of the National Centers
for Environmental Prediction (NCEP) joined with the NWS Office of Hydrology
(OH) and the NESDIS Office of Research and Applications (ORA) to pursue and
refine a modern-era LSM suitable for use in NCEP operational weather and
climate prediction models.Early in
this effort, NCEP carried out an intercomparison of four LSMs, including 1) a
simple bucket model, 2) the OSU LSM(known as the Coupled Atmospheric boundary layer - Plant – Soil, CAPS,
model land-surface scheme in some PILPS studies), 3) the SSiB model, and 4) the
Simple Water Balance model (SWB) of OH.The results of this intercomparison were reported in Chen et al. (1996,
see references therein for the four cited LSMs).As a result of the good performance of the OSU LSM in this study
and pre-existing hands-on experience with this LSM by various EMC staff members,
including Hua-Lu Pan and Ken Mitchell, EMC chose the OSU LSM for further
refinement and implementation in NCEP regional and global coupled weather and
climate models (and their companion data assimilation systems). The results of
the cited LSM intercomparison and the initial EMC refinements to the OSU LSM
were reported in Chen et al. (1996).

At
the beginning of the EMC LSM effort in 1990, the OSU LSM already had a 10-year
history.Its initial development was
carried out by OSU in a series of three papers (Mahrt and Ek, 1984; Mahrt and
Pan, 1984; and Pan and Mahrt, 1987).As
the EMC LSM effort unfolded during the 1990's, a series of NCEP extensions to
the OSU LSM were a) added by EMC and its GCIP/GAPP and other collaborators and
b) tested and validated in both uncoupled and coupled studies (see review of
these in Mitchell et al, 1999, 2000, and Ek et al. 2003).At NCEP, the LSM was first coupled to the
operational NCEP mesoscale Eta model on 31 Jan 96, with significant Eta LSM
refinements subsequently implemented on 18 Feb 97, 09 Feb 98, 03 Jun 98, 24 Jul
01, 26 Feb 02 12 June 02.In 1999, with
a) the new addition and testing of frozen soil and patchy snow cover physics in
the uncoupled LSM used for the NCEP-OH submission to PILPS-2d (Valdai, Russia),
and b) the growing number of external user requests for access to and use of
the NCEP LSM (e.g. GCIP/GAPP PIs), we decided the NCEP LSM had advanced to a
stage appropriate for formal public release (first in March 99).

In
2000, given a) the advent of the "New Millenium", b) a strong desire
by EMC to better recognize its LSM collaborators, and c) a new NCEP goal to
more strongly pursue and offer "Community Models", EMC decided to
coin the new name "NOAH"
for the LSM that had emerged at NCEP during the 1990s:

We in EMC strive to explicitly acknowledge both the
multi-group heritage and informal "community" useage of this LSM,
going back to the early 1980’s.Since
its beginning then at Oregon State University, the evolution of the present Noah LSM herein has spanned significant
ongoing development efforts by the following groups:

In
addition to “in-house” Noah LSM
development and validation by the above organizations, the following external
PIs (primarily GCIP/GAPP), have also performed valuable validations of the Noah LSM and its immediate NCEP 1990's
predecessors:

E.H.
Berbery and RasmussonU.
Maryland(ARM/CART)

C.
Marshall, Basara, and CrawfordU. Oklahoma (OU Mesonet)

Bastidas,
Burke, Yucel, Shuttleworth,

SooroshianU.
Arizona(ARM/CART, AZNET)

A.
Robock and L. LuoRutgers
U.(OU
Mesonet, ARM/CART)

A.K.
BettsAtmospheric
Res Inc(ISLSCP/FIFE)

C.D.
Peters-Lidard, WoodPrinceton
U.(TOPLATS
extensions)

L.
Hinkelman and AckermanPenn
State U.(ARM/CART)

T.H.
Chen, W. Qu, Henderson-Sellers, et al. RMIT(PILPS-2a)

E.
Wood, Lettenmaier, Liang, Lohmann:Princeton
U.(PILPS-2c)

A.
Schlosser, A.G. Slater, Robock, et al.U. Maryland(PILPS-2d)

R.
AngevineNOAA/AL(Flatland Exp)

L.
Bowling and D. LettenmaierUniv. Washington(PILPS-2e)

A.
Boone and J. NoilhanMeteo-France(Rhone/GLASS)

K.
Arsenault, B. Cosgrove, P. HouserNASA-HSB(LDAS)

See
Sec 10 for technical references on the above external validations.

Lastly,
one crucial collaborator deserves special
mention, namely the NESDIS Office of Research and Applications (Tarpley,
Ramsay, Gutman, Kogan, Bailey), which has been the source of critical
global surface fields of a) vegetation greenness and its seasonality and b)
realtime snow cover, plus important GOES, satellite-based, hourly surface
validation fields of c) land surface skin temperature andd) solar insolation, both on a 0.50-degree
lat/lon CONUS grid.

All
files are text files, except files NOAH_LSM_USERGUIDE_2.7.1.doc and
CHAMP_IL.doc, which are MS Word files.Download the tar file basic_with_validation.tar that contains all 15
files to your workstation.Use Unix
command “tar –xvf basic_with_validation.tar”to create a Proceed with a Noah
LSM execution test as described below.

First
uncompress the “*.Z” files with the Unix uncompress command.

The
uncompress yields five upper-case “*.TXT” files.These TXT files are
output files.Move these “TXT*
filesto a separate sister directory
for later comparison to the equivalent output files from your own local execution.

The
four lower-case files given by filenames

controlfile_ver_2.7.1

forcing98_with_validation.dat

namelist_filename.txt

soil_veg_namelist_ver_2.7.1

are
the four input files required during the execution of lsm.x.The “controlfile” (see Sec 5) contains model
configuration variables such as number and thickness of soil layers, number and
length of time steps, initial date/time of the simulation, lat/lon location of
the simulation site, initial conditions for all state variables, and
site-specific land classifications (integer indexes for vegetation-type,
soil-type, and surface-slope category).

will
launch and complete the 1998 one-year LSM simulation for the aforementioned
Illinois site, producing the same 5 “*.TXT” output files that you obtained
originally from the NCEP server.Normal termination of the execution is marked by the termination message
“STOP: 0”.Since all the “*.TXT” files
are ascii files, one can and should confirm that the 5 output files from the
local simulation agree very closely with the originally downloaded output files
from NCEP.

The
output file PRTSCREEN.TXT contains the output from “Print *” write statements
in the

MAIN
program.In this Version 2.7.1, these
are the block of three “Print *” statements locatedwithin the time-step loop in thePROGRAMMAIN source shortly
after the return from CALL SFLX .These
three Print * statements output the time step counter and the small surface
energy balance residual during each of the first 50 time steps and then every
50 time steps thereafter.

The
other four output files are the execution output data files of greater interest
and their contents are described in Sec 9.

One
important degree of freedom regarding these remaining four output files must be
cited here.The unit numbers for these
output files are 43, 45, 47, and 49, which are explicitly assigned in PROGRAM
MAIN (via variable names NOUT1, NOUT3, NOUT5, and NDAILY).The sign of these assigned unit numbers
controls whether the output is ascii or binary.The sign of all four unit numbers is determined by a signed
parameter (IBINOUT) read-in from the control file (see Sec 5).When the sign of IBINOUT is positive
(negative), the format of these four output files is binary (ascii).When the output format is ascii (binary)
then the extension *.TXT (*.GRS, meaning GrADS-readable) appears on the
generated filename.The ascii choice
(negative unit number sign) was invoked in the default control run you obtain
from the server.

3.2Basic

The
directory/mmb/gcp/ldas/noahlsm/ver_2.7.1/basic on anonymous server ftp.emc.ncep.noaa.gov contains the same files as
in the directory basic_with_validation except for 2 different files
DRIVER_BASIC.f and forcing_basic98.dat.The file CHAMP_IL.doc is missing as it is irrelevant.The basic driver DRIVER_BASIC.f reads the
near-surface input file forcing_basic98.dat that contains only the 7 observed
variables required for constructing Noah LSM forcing (cf. Sec.
6.2).This
basic driver is designed for reading data from regular surface sites that do
not measure surface fluxes or subsoil properties.

4.0SUBROUTINE SUMMARY AND CALLING TREE

Below,
we describe PROGRAM MAIN in the "Driver family" of subroutines (file
DRIVER_WITH_VALIDATION.f or DRIVER_BASIC.fas described in Sec. 3.2) and the "Physics family" of
subroutines (file NOAH_LSM_2.7.1.f ), comprised of physics
"sub-driver" routine SFLX and all subordinate subroutines.

9)invoke
LSM physics (CALL SFLX) to update state variables / sfc fluxes over one time
step

10)
write simulation output data each time step to four output files

The
section in driver PROGRAM MAIN associated with each of the above ten steps is
clearly delineated with comment line "DRIVER STEP n".

NOTE:
The section of PROGRAM MAIN for Step 6 includes optional code (presently
commented out) for calculating the downward radiation from the input air
temperature and humidity if the input forcing file does not provide it.

NOTE:The section of PROGRAM MAIN for Step 8
includes optional code (presently commented out) for invoking a User-provided
routine to calculate the surface exchange coefficient for heat (Ch) in place
ofthe default scheme.

The SFLX family of subroutines contain the physics of the
LSM and is rather self-contained.Each
user should become familiar with the argument list of SFLX.This argument list is thoroughly documented
at the top of subroutine SFLX.Once
becoming familiar with the argument list, users could if they so choose create
their own MAIN driver program with reasonably little effort.Calling SFLX each time step updates and
returns all the LSM state variables and all the surface energy balance and
surface water balance terms.In using
SFLX in a coupled atmospheric model, the output arguments needed from SFLX are:

The
filename of the control file is “controlfile_ver_2.7.1”.The user may want to have a printout of the
control file handy (about one page) when reviewing the comments below.

The
control file is read-in early in the MAIN program and provides inputs of the
following types of information:a)
valid location and start date/time of simulation, b) model configuration,

c)
name of input forcing file, d) integer indexes for land-sfc classes for the
site, e ) initial values of all the model state variables.

NOTE:The control file does not provide model physical parameters,
except for the lower boundary condition on the soil temperature (which should
be assigned the value of the annual mean sfc air temperature for the simulation
location).Physical parameters are set
in subroutine REDPRM and many of these parameters are dependent in REDPRM on
the veg-type index and soil-type index read from the control file.

The control file consists of
30 data lines that contain the following:

Line
01: LAT - simulation site latitude (positive N from equator, hundredths
of a degree)

Line
02: LON - simulation site longitude (positive W from Greenwich,
hundredths of a degree)

Note:The above serve only to document the valid
site of the input forcing data.

The physics do not use the above,
since forcing data provides downward solar radiation.

Above would be needed by a MAIN
driver that had to calculate downward solar radiation

Line
04: JDAY - Integer Julian Day (1-366) of start of forcing data (start of
simulation)

Line
05: TIME - 4-digit "hhmm" integer time of day (local) at start
of forcing data,

hh is 2-digit hour (0-23) and mm is 2-digit minute
(0-59).

Note:Except for use of JDAY to to temporal
interpolation of monthly greenness and albedo read-in later below, the above
JDAY and TIME serve only to document the valid start date/time ofthe input forcing data.The physics do not use the above, since
forcing data provides downward solar radiation.Above would be needed by a MAIN driver that had to calculate
downward solar radiation

Line
06: NCYCLES – number of times the integration will cycle through the
input forcing data

Note:In observed forcing data, the height of the
temperature/humidity observation (e.g. 2 m) is often different from the height
of the wind observation (e.g. 10 m ).When that is the case, we recommend using the height of the wind
observation for Z.

Line
13: SLDPTH - thickness values for the NSOIL soil layers in meters(chosen by user), starting with the
uppermost layer and proceeding downward

Note:We recommend that each succeeding soil layer
downward not exceed 3 times the thickness of the soil layer above it.For the common 4-layer configuration, we
recommend

Layer 1: 10 cm (.10 m)

Layer 2: 30 cm (.30 m)

Layer 3: 60 cm (.60 m)

Layer 4:100 cm (1.0 m)

Note:The physical equations in the LSM predict
the soil moisture/temperature state variables at the midpoint of each model
soil layer.

NOTE:!!Sum total of all soil layer thicknesses
should not exceed about 2/3 of depth parameter ZBOT.The
lower boundary condition TBOT of soil temperature is applied at the depth
specified by parameter ZBOT, whose current default value of -8.0 meters is set
in routine REDPRM (ZBOT follows negative sign convention for soil depth), but
this default can be changed via the optional NAMELIST I/O in REDPRM.

Line
14:- filename of the first input
forcing file (up to 72 characters)

Line
15:- filename of the second input
forcing file (up to 72 characters)

Note:
see above discussion of logical variable "L2nd_data

Note:
the two forcing files may be the same name (used for both spin-up and
production years)

NOTE !! : User should contact NCEP Point of Contact given
at top of Page 1 for recommended values for Lines 12-18

Line
20: SHDFAC- 12 monthly values
of green vegetation fraction for simulation site

NOTE !!See contact point at top of this User's Guide to get monthly
vegetation greenness values for your simulation site of interest.

NCEP
now sets monthly SHDFAC using the global database and publication of

Gutman, G. and A. Ignatov, 1998: The
derivation of the green vegetation fraction from

NOAA/AVHRR for use in numerical weather prediction
models.International Journal

of Remote Sensing, 19,
1533-1543.

This
latter work provides a 5-year, monthly mean, global database of green
vegetation fraction at 0.144 degree resolution, obtained from NDVI.The authors forcefully argue that the two
AVHRR channels that are used to derive NDVI do NOT provide sufficient degrees
of freedom to derive BOTH vegetation greenness and LAI independently.They instead argue for embracing all the
seasonality of vegetation in the greenness fraction and holding the LAI at a
fixed constant annual value in the range of 1-5 (thus LAI becomes a tuning
parameter).NCEP has obtained
reasonable behavior with LAI=4.

Line
21: SNOALB – maximum albedo expected over deep snow

Note: NCEP takes the above from the 1-degree, N.
Hemisphere, digital database of

Line
22:ICE – Flag to invoke sea-ice
physics(always set to 0 for land-mass simulations)

Note:The integer flag“ICE” forces branch to sea-ice physics in LSM.

Be aware that this ICE flag has no bearing on soil ice
physics in NCEP LSM.

Line 23:TBOT
– set to the climo annual mean sfc air temperature (K) for the modeled site

.

Note:TBOT serves
as the annually fixed, soil-temperature bottom-boundary condition at a soil
depth of ZBOT.ZBOT is currently set at
a default 8-meter depth (-8.0) in routine REDPRM.ZBOT is the assumed nominal soil depth where the amplitude of the
soil-temperature annual cycle is near zero (e.g. about double the e-folding depth
in the soil of the annual cycle of surface air temperature).

Initial conditions for all state variables follows:

Line 24: T1 – initial skin temperature (K).Can be set to initial air temperature.Model physics

NOTE:Initializing
soil ice (case of SH2O less than SMC) is very difficult.Recommend starting the model run in the warm
season and letting the physics spin-up soil ice, or running multi-year spin-up
cycles.

Line 28:CMC
– initial canopy water content (m).Set
to zero as physics rapidly spins this up.

As is typical with many off-line, uncoupled LSMs, the NCEP
LSMrequires the following near-surface
atmospheric forcing data, preferably at 30-minute time intervals (or
interpolated to

30-minute time intervals or smaller from say 1-6
hour interval observations-- Aside
note: for observation intervals longer than 1-hour, the incoming surface solar
insolation needs to be interpolated with a solar zenith angle weighting, in
order to capture the full amplitude of the diurnal solar insolation).

Air temperatureat height Z above ground

Air humidityat height Z above ground

Surface pressureat height Z above ground

Wind speedat height Z above ground

Surface downward longwave radiation

Surface downward solar radiation

Precipitation

For
the example one-year LSM simulation provided with this User’s Guide, we were
extremely fortunate to benefit from the collaboration of GCIP/GAPP-sponsored PI
Tilden Meyers of NOAA/ARL, who operates a flux site located just south of
Champaign, IL (40.01 N lat, 88.37 W lon).

The
site characteristics and observing instrumentation are described in the MS Word
document

CHAMP_IL,
provided by courtesy of Tilden Meyers, and available in same directory as this
User’s Guide.

The
1998 forcing file from the above flux site is available as filename
“forcing98_with_validation.dat” in the same directory as this User’s
Guide.This file contains one record
for each 30-minute observation time and the file spans the entire calendar year
of 1998 (hence 2 X 24 X 365 = 17520 records).Each 30-min record provides the following 33 observed variables (including
the 7 required LSM forcing variables, marked by “**”), listed in the order they
appear in each record of the file:

In the LSM, program MAIN
reads in all 33 of the above variables at each time step via the call to
subroutine READBND, which also fills in occasional missing observations.Missing obs are very sparse and virtually always
involve missing values of the wind speed (u_bar at 6 m), for which the READBND
software substitutes (w_speed at 10 m with a reduction factor).Finally, the last section of routine READBND
performs unit conversions on “rain”, “Ta”, and “Pres” to convert them to the
units expected in the call to SFLX .

In addition to the
LSM-required atmospheric forcing variables in the above list, the other
variables in the list represent either a) independent validation data or b)
useful initial conditions for the LSM state variables.LSM initial conditions are discussed in the
next section.

At each time step in the
MAIN program, after the return from the physics update in CALL SFLX, useful LSM
validation data from the above observation file is written out to validation
output file OBS_DATA.TXT via call to routine PRTBND (e.g. LE, H, GHF, RNET,
IRT, and the layer by layer soil moisture and temperature).

This
file contains one record for each 30-minute observation time and the file spans
the entire calendar year of 1998 (hence 2 X 24 X 365 = 17520 records).Each 30-min record provides the following 9
observed variables (including the 7 required LSM forcing variables, marked by
“**”), listed in the order they appear in each record of the file:

jdayJulian
Day

timeLST,
half hour ending

**Taair temperature (C), at 3 m

**RHrelative humidity at 3 m

**Pressurface pressure in mb

**Rgincoming solar radiation (W/m2)

**raintotal rain for half hour (inches)

**u_bar average wind vector speed at 6-meters (m/s)

**LW_indownwelling longwave from sky (W/m2)

7.0 LSM INITIAL CONDITIONS

The LSM requires input values (read-in from control file in routine
READCNTL, see Sec 5 for details on units) of the following state variable
initial conditions :

Typically,
a number of these state variables are not observed at a given validating
observation site.The following initial
variables were not available in the site observation file (obs98.dat):

SNEQV,
SNOWH, CMC, nor SMC (and SH2O) below 60 cm

Since
January 1998 was mild (El’Nino) at the given site, we assumed a) zero snow
cover (SNOWH=0.0, SNEQV=0.0) and b) zero soil ice (SMC=SH2O), plus we set
CMC=0.

While
we in general found the physical behavior of the observed data in file
obs98.dat to be very good, inspection of the observed soil moisture at the 20 and 60 cm levels showed them to be
virtually time invariant over the entire year, despite substantial wetting and
drying periods.Hence their accuracy is
very suspect.

It is typical for
LSM simulations at a particular observation site to be hampered by non-observed

(e.g.
snowdepth, frozen soil moisture, deep soil moisture ) or ill-observedinitial state variables (.e.g. soil
moisture).Facing this dilemma, the
Project for Intercomparison of Land-Surface Process Schemes (PILPS) has come to
urge modelers to use a one-year spin-up protocol, whereby the simulation for a
desired period (1998 here)is preceded
by a spin-up year (say 1997 in this case) where the spin-up year forcing is
repeated several years to allow the LSM to essentially achieve
equilibrium.

Tilden
Meyers provided us with the 1997 forcing data for his site, and we proceeded to
execute the PILPS-recommended spin-up protocol to provide all initial soil
states for the one-year 1998 production run provided in this directory.

Specifically,
in a prior run using the same model configuration as in the control file given
here and using L2nd_data = .false., NCYCLES= 10, and the aforementioned 1997
forcing file we call "obs97.dat", we executed a 10-year spin-up run
over the 1997 annual cycle in order to derive initial conditions of soil state
and snow state (turned out zero snowpack, because of warm fall and early winter
in 1997) for the 1998 production run provided here in the directory with this
User's Guide.In practice, a full
10-years of spin-up is not needed.We
generally recommend 3-5 years of spin-up.

8.0SPECIFYING MODEL PARAMETERS

The
vast majority of the Noah LSM
land-surface parameters are set in subroutine REDPRM.However, the assignment of some land-surface parameters have not
yet been “collected” into the REDPRM setting and remain buried deep in the LSM
code.We feel these exceptions are
primarily parameters of secondary or tertiary importance.A few exceptions may be some parameters
used in the snowpack physics, such as the parameter that controls the amount of
supercooled water allowed in the soil over a range of sub-freezing
temperatures.We are working to
identify such parameters and bring them into the REDPRM setting in a future
release.

In
a broader sense, one should also consider the number (NSOIL) and thickness
(SLDPTH) of the soil layers (especially thickness
of top soil layer) specified in the control file to be adjustable
parameters.

Before
proceeding further in this section, the reader should have on hand a copy of
the subroutine REDPRM.

In
REDPRM, we define the NAMELIST named "/SOIL_VEG/", which includes ALL
the parameters defined in REDPRM, including parameter arrays whose elements
depend on soil type, vegetation type, or slope type.Moreover, this namelist includes three variables that
respectively define the number of classes (up to a maximum of 30) that we carry
for soil type, vegetation type, and slope type.With the powerful and robust flexibility of the namelist
construct, we can even make wholesale changes to the soil and vegetation
classification scheme used and the soil and vegetation parameters associated
with the change in classification.Thus
via the namelist read, we can change as little as one single universal
parameter, or multiple- element parameter arrays associated with a
classification, or the number of classification categories themselves, or a
combination of these, all without any recompiling of source code.

One
exercises the above flexibility through the input filename called
"namelist_filename.txt", which is read-in by routine REDPRM.This 1-line 50-char text file provides the
name of the namelist file, which the routine REDPRM then reads in as well.By this mechanism, one can carry multiple
namelist files (providing different parameter sets) in the same execution
directory.The contents of the 1-line
file "namelist_filename.txt" thus acts as a pointer to the namelist
file you wish to read-in during a given execution.

Every
namelist file so pointed to must begin with the following syntax:

$SOIL_VEG
LPARAM = .FALSE.$

or

$SOIL_VEG
LPARAM = .TRUE.$

with
the latter followed by at least one or more defined parameter values.

We
recall that the beginning of Sec 3 listed all the filenames in the directory
/ver_2.7.1 with this User's Guide (Noah_LSM_USERGUIDE_2.7.1.doc).Inspecting the contents of filename
"namelist_filename.txt" therein, we find that this file points to the
filename ""soil_veg_namelist_ver_2.7.1".On inspection we find the contents of this
file to be

$SOIL_VEG
LPARAM = .FALSE.$,

hence
ALL the default values of the parameters defined in REDPRM will be retained
unchanged.

If
the contents of "namelist_filename.txt" instead pointed to filename
"namelist_chg_example", then we find on inspection that the contents
of the latter file are

In the above example, our execution will
utilize 1) new values for all the elements of array NROOT, 2) a new value for
the 7-th element of the array of roughness lengths (this element corresponding
to veg class #7, or perennial grassland), and 3) a new value for the scalar
surface runoff parameter REFKDT.

Below, we will review ALL the parameters
defined in REDPRM.All these parameters
are included in the NAMELIST /SOIL_VEG/, which is specified in routine REDPRM
as

NAMELIST
/SOIL_VEG/ SLOPE_DATA, RSMTBL, RGLTBL, HSTBL, SNUPX,

&BB, DRYSMC, F11, MAXSMC, REFSMC, SATPSI, SATDK, SATDW,

&WLTSMC, QTZ, LPARAM, ZBOT_DATA, SALP_DATA, CFACTR_DATA,

&CMCMAX_DATA, SBETA_DATA, RSMAX_DATA, TOPT_DATA,

&REFDK_DATA, FRZK_DATA, BARE, DEFINED_VEG, DEFINED_SOIL,

&DEFINED_SLOPE, FXEXP_DATA, NROOT_DATA, REFKDT_DATA, Z0_DATA,

&CZIL_DATA, LAI_DATA, CSOIL_DATA, SMLOW_DATA, SMHIGH_DATA

In the above
list, there are five kinds of land-surface parameters,
reviewed in order below.

Note:CZIL is a
tuneable parameter, which controls the ratio of the roughness length for heat
to the roughness length for momentum, and is known as the Zilintikevich
coefficient. This parameter effectively allows tuning of the aerodynamic
resistance of the atmospheric surface layer.Increasing CZIL increases
aerodynamic resistance.For a full
description and example impacts of this primary parameter, see the article by

NOTE: REFKDT is a tuneable parameter that significantly
impacts surface infiltration and hence the partitioning of total runoff into
surface and subsurface runoff.Increasing REFKDT decreases surface runoff.See next publication: